


To Finish It, Once And For All

by afteriwake



Series: Lingering Winter [3]
Category: Bleach
Genre: Gen
Language: English
Status: Completed
Published: 2012-10-16
Updated: 2012-10-16
Packaged: 2017-11-16 11:11:28
Rating: General Audiences
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 4
Words: 4,308
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/538812
Author URL: https://archiveofourown.org/users/afteriwake/pseuds/afteriwake
Summary: <blockquote class="userstuff">
              <p>The battle for Fake Karakura Town took a turn when new reinforcements arrived, but would it matter, in the end?</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> This deals with two pet theories of mine: (1) Isshin was the 11th squad captain that Kenpachi “killed,” and (2) he was head of the Shiba clan while he was in the Gotei 13. More will be explained, but I’d been dying for Isshin, Yoruichi and Urahara to have a big damn heroes moment in the series, so that’s how I’m writing it. Thanks to **thiscanbegin** and **kellenanne** for the support and advice.

He was going to win.

That thought ran through everyone’s heads as Aizen effortlessly fended off attacks from his left, from his right, from the front and from the back. Hachi was busy healing Hiyori, Unohana was working on Hinamori and Hitsugaya was engaged in a fierce battle with Gin much farther away, so Kira was the only one avoiding the fight and trying his best to heal everyone else, but it was a losing battle. In fact, Kira mused as he worked on healing Komamura’s arm from the same rooftop that the other healers were on, all of this was a futile effort. Aizen would win, and they would all be dead. Still, it didn’t stop him from trying to help.

And then, suddenly, it went quiet. He looked up and saw Ichigo, the Captains, the Lieutenants the Vaizards _and_ Aizen stop fighting as the passageway was opened up and three people emerged from it, the same way the Vaizards had shown up. He didn’t recognize them, but their appearance seemed to give Aizen pause.

“Sorry we’re late!” Urahara called out. He looked over at the woman to his left and then to the man at his right and said something quietly to the man. The man had on shinigami robes, and the robes of a Captain at that, but Kira did not recognize him at all, and he knew all thirteen of the Captains on sight. This man…he looked familiar.

Aizen nodded. “Kisuke. Yoruichi. I see you’ve finally joined us.” He peered closer, and then his eyes widened slightly. “Isshin Shiba. It _has_ been a long time.”

Ichigo, who at this point had been pushed back to the far end of the attack, whirled around and stared in shock. “Dad?!?”

Isshin nodded, a grin on his face. “Where did you think you got your powers, Ichigo?” Then he turned to Aizen. “I think it’s time to finish things, once and for all. Don’t you think?”

“I can see you’re still as battle hungry as ever, Isshin,” Aizen said with a nod.

“No, I’m not, actually. Just when it comes to you.” Then he turned to Ichigo again. “We’ll talk later, and I’ll explain. For now…let’s just finish this. I’ll be by your side.”

“Are you that good?” Ichigo asked.

“One of the best,” Yoruichi said, a slightly smug look on her face. “I should know. I helped train him.” Then she turned away from Ichigo and looked over at Aizen, her smirk widening. “I never did trust you, Aizen. And I knew the one person in Soul Society with at _least_ as much reiatsu as you was Isshin. I trained him in _everything_ I know.”

Aizen’s eyes widened just ever so slightly, and then the affable smile on his face widened a little more. “Your secret weapon, then?”

“Something like that,” Isshin said.

Kira looked away from the action to see Kyoraku near him, a smile on his face. “Captain Kyoraku, who is that man?” he asked.

“That is Isshin Shiba, former 11th Captain. We all thought Zaraki had killed him,” he said with a slight laugh, holding his broken arm close to his chest. “This suddenly explains a lot about young Ichigo, how a human could have such strong reiatsu, and why none of us realized he was Isshin’s son, with the name change.” He glanced at Kira. “If Yoruichi trained him in everything she knew, we now have a very good chance at winning this fight. If you think Ichigo has an abundance of reiatsu, Isshin has _more_.”

Unohana took a moment away from Minatzuki and came over to the trio. “Isshin was once the 3rd seat of my squad,” she said. “I was very sad to lose him when he challenged the head of the 11th squad for the position of Captain. He is a great healer.” She smiled slightly. “I was the only one he trusted with the knowledge that he had faked his death. I healed his wounds from that fight. I helped him escape to the human world and told him that I had heard Kisuke was there from my Lieutenant.”

Kyoraku‘s eyes widened. “Retsu, you know what Yama-jii would do to you if he knew?”

She nodded. “I do,” she said, looking down.

Sudden insight hit Kyoraku as he looked at her. “You loved him, didn’t you?” he asked quietly.

“Yes,” she whispered. “It hurt to see him go, but if he stayed Zaraki would surely have killed him.”

Kyoraku moved to Unohana’s side and placed an arm on her shoulder as the entire area became charged with an enormous release of reiatsu. “And if he dies now?”

She looked up and at him, and for the first time in their entire long history together, Kyoraku saw a blazing fury on her face. “If Aizen kills him he will not live long enough to see another day.”

Kyoraku nodded, then turned back to the spectacle above them. “Then let’s hope he really is as powerful as we all think him to be.”


	2. Chapter 2

Ichigo remembered Kenpachi’s overwhelming presence during their fight, and realized it was _nothing_ next to his fathers. The amount of power that radiated from Isshin was staggering, and it froze Ichigo in his tracks. He took this moment to briefly think about what he was seeing. He was seeing his _father_ with Captain‘s garb and a sword and he was going to fight Aizen, a man who had just been beating down every opponent that had come his way. And Aizen had paused, he had stopped what he was doing, and he had accepted the challenge of fighting Isshin Kurosaki. The one thing Ichigo didn’t get is why Aizen called him Isshin Shiba, though. He remembered the Shiba clan, Ganju and Kuukaku, and he had learned about their brother Kaien, but there was no mention of an Isshin, and certainly not his father.

Suddenly he felt a slap to the back of his head. “Pay attention!” Yoruichi said. “Your father is going to need your help. Like all of the Captains, we assume he’s seen Aizen’s shikai. And if you still haven’t, you need to be his eyes. Be ready.”

Ichigo nodded and forgot about the overwhelming reiatsu pushing against him. He opened himself up to full strength and found the pressure coming from his father easier to deal with. He noted that Isshin had pulled his sword out. Suddenly, he was very curious to know his father’s sword name and call. 

“You remember my shikai, don’t you?” Isshin said to Aizen. Then he glanced at his sword briefly. “Sundan, Sanmenkyou.” There was a sudden rushing of air around him, and Ichigo saw that his simple sword had become a tsurugi. 

“Yes, I remember,” Aizen said with a nod. “I watched your fight with Zaraki Kenpachi. Your shikai has the ability to mirror an injury on the body. If I were to let you get close enough to, say, cut my left cheek, my right cheek would be cut as well, in a mirror reflection of the first injury.”

“Very good,” Isshin said. “Wouldn’t want you to think I’m getting too smug here.”

“But you are, if you think I’m going to let you get that close,” Aizen said. “Remember, you’ve seen Kyouka Suigetsu as well.”

“But I have a secret,” he said with a slight shrug. Then he held his sword in front of him. “Bankai.” The sword glowed white for a moment, but its shape did not change. The only thing to change was the color of the blade, which became white, while the hilt turned red. “There. I think we can fight now.”

Aizen’s eyebrow raised ever so slightly. “Using bankai already? You really must want to fight me.”

“I really just want to kill you,” Isshin replied. “It would make the world of the living safe again, and that is what I want. I don’t fight for Soul Society. I fight for my family.” He glanced at Ichigo. “I fight for my son, and I fight for my daughters. And I fight to keep my way of life safe from you.”

“Very pretty speech, Isshin,” Aizen said, his smug look settling on his face as well. “Let’s put things to the test, shall we?”

With lightning quick speed, Aizen moved from where he was standing to where Isshin was standing. Or had been standing, at any rate; when Aizen got there, Isshin moved behind him and slashed his arm. It wasn’t a deep cut, but it was enough that blood welled to the surface. “Ichigo!” Isshin yelled.

Ichigo looked at the scene, then charged forward, sword at the ready. His sword clashed with Aizen’s , and they remained locked for a moment.

“You’ve tried to beat me and you’ve failed,” Aizen said to Ichigo. “Not even your father can help you.”

Ichigo took a step back, but this time Aizen’s words did not affect him as they had before. Instead, they strengthened his resolve. He _had_ to believe that his father had great power, that there was hope, that they would win. He knew his father fought for him, and for Karin and Yuzu, and Ichigo himself had others to fight for. He fought for Orihime and Uryuu, Chad and Tatsuki, Mizuiro and Keigo and even Chizuru. He fought for all of Karakura Town, and he _would not_ let Aizen win.

He heard a gasp from the side, just barely above the sound of clashing swords, and heard Unohana cry out a name. And suddenly he realized what she was saying: what she saw, what they all saw, was Ichigo fighting Hitsugaya and about to stab him in the heart. Ichigo could sense Hitsugaya far behind him, oblivious to the three way fight between himself, Isshin and Aizen. “It’s not him!” Ichigo cried back as Isshin made another attack at Aizen, slicing his side. And then it hit Ichigo: _Isshin wasn’t fooled by the illusion!_ Isshin had struck Aizen, and he had to know it was Aizen and not Hitsugaya. Something had changed in this fight, something significant.

Aizen used shunpo to get out of the tight spot. “Interesting,” he said, looking at the cut on his arm, and then down at the cut in his side Isshin had inflicted. Blood was welling at that cut as well. “Your bankai, Isshin…”

“Deflects all attacks directed at me,” Isshin said. “Kisuke surmised that it could deflect an illusion attack, and he was right. I can see you, Aizen, no matter what illusion you try to use. ”

Aizen’s eyes widened, and for a moment something different passed in his eyes. Ichigo couldn’t tell what, but it _almost_ looked like fear. But then it was gone, and the smug look crossed his face again. “Then I’ll just have to make sure you don’t see me at all,” Aizen said.

Aizen looked at his sword, and then said one word: “Shimanagashi.” His sword, like Isshin’s did not change shape, but the blade became red and the hilt white, a mirror image of Isshin’s except for the type of sword. Then, instead of leveling an attack at Isshin, he turned and fired off a shot towards Ichigo. All Ichigo saw was a flash of white light, and then he saw nothing. He clutched his sword tightly, but not being able to see made him panic and stumble, and he forgot that he was in the air. After a moment, the force holding him up crumbled, and he fell.

“Ichigo!” Isshin yelled. He turned to Aizen. “What did you do?”

“I merely took away his sense of sight,” Aizen said, raising one shoulder in a negligent shrug. “Your bankai may protect you, but it doesn’t protect your son.”

Isshin was about to reply when he saw that Yoruichi had burst into action, using her incredible speed to catch Ichigo before he impacted with the ground. “But on the other hand, your bankai doesn’t affect me. There was no point in you using it, other than to try and rile me up by using it against Ichigo.”

“Perhaps,” Aizen said. “Or perhaps I used it to take the greater threat out of the battle.”

“If you truly believe Ichigo Is a greater threat than I am, Aizen, then you are _very_ much mistaken.” He looked at Aizen and then grinned. “My bankai is not the only weapon I have left.”

“And what other weapon do you have left?” Aizen asked.

“This,” Isshin said. He reached up to the top of his face, and pulled down. When he was done, there was a Hollow mask on his face, one very similar to Ichigo’s but with different markings and more coverage of his head. “Ichigo was not the first person Kisuke used this technique on. I had many years in Soul Society to perfect my technique, and once you learn something you do not forget it.” He raised his sword again and leveled it at Aizen. “Come and get me,” he said as his level of reiatsu grew even more.

Aizen’s eyes widened again, ever so slightly, and then the look disappeared as he powered up his own reiatsu. “Gladly.”


	3. Chapter 3

Yoruichi brought Ichigo to Unohana. “I caught him,” she said, setting him down on the rooftop.

Ichigo scrambled to sit up once he felt something solid underneath him. “I can’t see!” he said.

Unohana put a hand on his forehead and gently pushed him back down. “I don’t know if I can heal you, Ichigo. I never knew anything about Aizen’s true bankai. This may be an injury that no one can heal.”

“How did we not know this was his bankai?” Kira asked.

“His shikai creates an illusion,” Kyoraku said. “He probably created an illusion of a different bankai to achieve Captain status.” He moved his arm slightly, the one that Unohana had healed as they’d watched the fight. “So, Isshin is a lot like you, Ichigo. He has Hollow powers as well as shinigami powers. Interesting.”

“Someone please tell me what’s going on?” Ichigo asked quietly, turning his head in the direction of the fighting.

“They’ve abandoned the taunts and are into serious fighting,” Kyoraku said. “Right now, your father has the upper hand. But after seeing what happened with Tousen, I wouldn’t be surprised if Aizen has attained Hollow powers as well. If Isshin is to win this fight, he must do it soon.”

Yoruichi turned to watch the fight. “I hope Isshin remembers that he knows Shunko and to use it if Aizen once again gains the upper hand.”

“You taught him Shunko?” Kyoraku asked, raising an eyebrow slightly.

She grinned. “As I said earlier, I taught him everything I know. He may not be as strong as General Yammamoto, but he is one of the strongest shinigami that I have ever met, even stronger than both of you,” she said, indicating him and Unohana without looking at them. Then she turned to Kyoraku. “If you’re feeling better, care to join me and Kisuke as a contingency plan in case Isshin needs us?”

Kyoraku nodded. “Yes.”

“Good,” she said with a nod. “Let’s go.”

The two of them left the rooftop to join Urahara, leaving Ichigo, Kira and Unohana alone. “Your father is an exceptionally good fighter,” Unohana told Ichigo. “He’s meeting every attack Aizen is making, and sometimes he has the upper hand.”

“He may still win?” Ichigo asked, turning to the sound of her voice.

“I have great confidence that he will,” she said with a nod, even though she knew he could not see it.

“Why did Aizen call him Isshin Shiba? He’s not related to Ganju and Kuukaku, is he?” Ichigo asked.

“He was the head of the Shiba clan,” Unohana explained. “He was the eldest brother to all of them, by quite a few years. He made it through the academy first, long before Kaien, and became my 3rd seat almost right from the start. He was an exceptional healer.”

“He’s a doctor,” Ichigo said. “He runs a clinic.”

“It’s good to know that he continued to heal people,” she said. “After the Captains and Lieutenants who were turned into Hollows disappeared, and Kisuke, Yoruichi and Tessai among them, he fought the 11th squad Captain at that time for the position of Captain, and he won. He left my squad and was Captain for almost eighty years, before Zaraki arrived and challenged him.”

“What happened?”

“Isshin knew Zaraki would kill him if they fought. He knew he needed to fake his death and escape. He came to me and we devised a plan, though Zaraki did almost kill him during the fight. I healed him in secret and helped him escape to your world, and told him I had heard rumors from my Lieutenant that Kisuke was in Karakura Town. And that is the last I heard from him, until today.”

Ichigo was quiet. “Thank you.”

Unohana was surprised, just a bit. “What for?”

“If you hadn’t saved him, I never would have existed,” he said quietly. “So…thanks.”

Unohana smiled slightly. “You are welcome, Ichigo.”

The sound of fighting grew louder, and Ichigo turned back to the sounds of violence. “What’s happening now?”

Unohana watched, and then frowned. “I think Aizen has just regained the upper hand.”

“How?” asked Ichigo.

“He has pulled on a Hollow mask,” she said sadly. “He achieved Hollowfication for himself, and his reiatsu has increased accordingly.”

“Damn,” Ichigo muttered.

Unohana nodded. “I agree. Let us hope that Yoruichi can get him to use Shunko, so that he once again has the advantage. We most certainly need it now.”


	4. Chapter 4

It was an intense fight. There were times when the fight was in Isshin’s favor, and times when it went in Aizen’s favor, and times when it was a fairly even match. They used attacks that pushed the other through buildings, left huge divots in the streets below, and caused small shockwaves with the intensity of sword against sword. Both men were cut, the white outfit of Aizen’s stained red in many places, and deep gashes cut in Isshin’s robes and skin with blood welling up on the exposed skin. 

But they were fighting alone. Even when the tide turned against Isshin, no one interfered, with the only exception being Yoruichi yelling “Remember everything I taught you, Isshin! _Everything_!”

With that he paused, and stepped away from the fight, casually blocking Aizen’s last attack. He pointed his sword at Aizen, and then suddenly something like lightning filled the air and crackled around Isshin. The spiritual energy was so great that the nearby buildings were beginning to shake, including the rooftop where the healing was going on. By the time it had gotten to this point, Kira and Urahara had brought up as many injured people as they could to get them out of harm’s way while the battle commenced, and they were joined by Soifon, Yoruichi, Kyoraku and a triumphant Hitsugaya and a wounded Hisagi. All eyes were on the now destructive fight.

Soon, the energy around Isshin was so great that the top of his robe was ripped to shreds, leaving him naked from the waist up. Yoruichi was grinning openly, and looked at Soifon. “ _This_ is Shunko when it’s mastered,” she said. Soifon, for all her seriousness, looked on with a sense of pure awe.

Isshin looked at Aizen, moved right next to him, aimed, and then fired off an intense blast of energy. As fast as Aizen was, he didn’t manage to escape the brunt of the blast, and he was hurled backwards, colliding into a building. He got up, and rushed at Isshin, sword drawn. Isshin waiting until he was close and blocked his blade with one hand before hitting Aizen in the face with his other, combining it with the energy swirling around him. Aizen was thrown to the ground, and Isshin quickly followed.

“You…will not…win,” Aizen said as he stood up. His Hollow mask was broken, and for the first time the smug look on his face was wiped away completely and clear, raw anger was etched on every line of his face and burned in his eyes.

Isshin did not reply. He raised his sword, and the energy swirled around it, becoming an extension of his body. “You have lost, Aizen.”

Aizen looked at Isshin one more time, and rushed towards him. Isshin held his sword steady, and then when Aizen was close enough, he slid his sword through Aizen’s chest. Aizen coughed blood, some of it landing on Isshin’s bare chest, as he looked down.

It was anticlimactic, Aizen thought to himself as Isshin pulled his sword out of his body. It was not supposed to end like that. He was supposed to become King of Heaven, not to die at the hand of a former Captain, a man who Aizen had barely ever given a second glance to, a man that he realized now he had sorely underestimated. He had one final trick left, though. He had a Resurrección, and if it didn’t work…

Before he could say the call for transformation, though, Isshin struck one final blow. Aizen’s guard had been down, the one protecting the back of his neck and keeping the neck area toughened, and with one clear shot Isshin cut off his head. It landed next to Aizen’s body with a thud, and soon the body fell next to it.

The fight was over, and Isshin had won.

Suddenly, there was a cry, and all attention turned to a forgotten villain, Wonderweiss. Isshin, though exhausted, turned to face an enemy who had just stood there and watched. The two eyed each other, but then another passageway opened up, and the people who had been stranded in Hueco Mundo came through, most of them directly in front of Wonderweiss.

“Another enemy?” Kenpachi said with a wicked grin as he licked his lips.

Wonderweiss looked at them, and then at the people on the rooftop, and opened his own passageway up, one that lead back to Hueco Mundo. He took the monstrosity he had with him and escaped with such speed that no one was able to stop him, and the portal closed behind him.

“He may become a problem,” Unohana said quietly to Kyoraku. “Just because Aizen is dead does not mean we are completely free of the threat.”

“I know,” he said with a nod. Then he turned to those on the rooftop. “We should probably go down to the street now, those of us who are able.”

Kyoraku, Urahara, Yoruichi and Shinji began to head off the rooftop. Ichigo sat up, blinked his eyes a few times, and then turned to Unohana. “I can see,” he said.

“The effect must have ended when Aizen died,” she said with a smile. “Go. I think you need to see your father now.”

He nodded and got up, following everyone down to the street below, where they were joined by those returning from Hueco Mundo. Ichigo was surprised to see Nel, the Great Desert Brothers and Grimmjow with the group. Grimmjow was the most surprising, as the last time Ichigo had taken a good look at him he’d assumed he was dead.

General Yamamoto had also joined them at that point, and was looking at Isshin as he removed his Hollow mask. “Isshin Shiba,” he said. “Well done.”

“It’s Isshin Kurosaki now.” Isshin looked at him, and then shrugged slightly. “You could have done this at any time, you know,” he said. “I didn’t need to save the day.”

“I think not,” Yamamoto replied. “You have skills that I lack.” He then turned to everyone gathered there. “We are triumphant. The threat is gone.”

“There’s still that kid left,” Kyoraku said. “I think he’s more powerful than we realize.”

“We can deal with him at a later date,” Yamamoto replied. “For now, Soul Society and the world of the living are safe.”

Kenpachi looked at Isshin, narrowing his eyes. “I killed you.”

“I faked my death,” Isshin said with another slight shrug.

Kenpachi looked at him, and then glared slightly. “Then I’m not the best fighter in Soul Society, because you’re still alive. I want a rematch.”

Isshin shook his head. “I think my days of fighting are going to be behind me again,” he said, sheathing his sword, which had returned to its normal state. “Right now, I need to speak with my son.” Isshin moved through the crowd with Ichigo following, and they parted to let him and Ichigo through. For the first time Ichigo saw that the battle had ended outside the fake version of their home. “A bit ironic,” Isshin noted, looking at the building.”

“Captain Unohana explained some things,” Ichigo said. “Why didn’t you tell me?”

“There wasn’t time, or need, until now,” Isshin said. “Before Shinji left, he warned Urahara that they might need more reinforcements. He contacted me and the rest…you were here, so you know.”

“What are we going to tell Karin and Yuzu?” he asked. “We have family in Soul Society.”

Isshin’s eyebrow raised. “You’ve met your cousins?”

He nodded. “Kuukaku and Ganju.”

“What about Kaien?” Isshin asked, confused.

“He’s dead,” Ichigo said quietly.

Isshin bowed his head. “I didn’t know that.”

“He was taken over by a Hollow, avenging his wife. Rukia had to kill him.”

Isshin was quiet for a few moments, and then looked up and sighed. “I suppose I owe them an explanation. And Yuzu and Karin as well. But for now…” He put a hand on Ichigo’s shoulder. “For now, let’s make sure your friends are all right.” Ichigo nodded and Isshin’s hand dropped away as they returned to the crowd, and to the subdued celebration that was taking place as the Winter War had finally come to its end.


End file.
